A joint effort led to the inclusion of full-depth reclamation (FDR)* in the Federal Aviation Association (FAA)’s FAA Advisory Circular 150/5370-10H (previously: Standard Specifications for Construction of Airports).
“The net result of this team effort is a standard that now includes
FDR specification language, which allows engineers to easily
and quickly incorporate the FDR strategy into airport rehabilitation plans, while at the same time, streamlining the
overall pavement rehabilitation process.”
Gary Mitchell, VP of Airports and Technology-American Concrete Pavement Association (ACPA) said it began when the FDR was being promoted to airport owners, most notably by the Southeast Chapter-ACPA. Mitchell said the SE Chapter and other ACPA promoters have done an outstanding job promoting FAA projects, and added, “They’ve completed several [projects] where they’ve rehabilitated pavements with in-place cement-treated base material, but those projects often had to be completed through a modification of existing airport pavement construction standards. [Many] times, promoters would discuss projects with engineers who expressed interest, but then the engineers would explain that they would have to do a modification of standards and then would often hear that there wasn’t enough time to do so.”
[Therefore], it is often difficult to get engineers to push a modification of standards through the FAA because it DOES take a long time for them to go through the process, which involves:
1) The engineer submitting the modification request
2) Reasoning with the FAA district office or Airport District Office (ADO)—Mitchell said, “The ADO can make decisions on some modifications, but for that particular type of modification, they would have to
3) Send modification up to the region for review, then if they agreed with it, they’d have to
4) Send it to the engineers at FAA headquarters…”
5) If they’ve approved it, Mitchell said the response would then
6) Follow the same path back to the ADO and
7) Then to the Engineer …
“In all, the process could take anywhere between a few weeks to as much as three months. It was really a burdensome process and it wasn’t done as often as we would have liked, so the FDR strategy wasn’t considered an alternate on a lot of projects because it was too difficult to get the modification quickly,” Mitchell said.
All of this changed during the process when Gary, with support from contractors and other members of ACPA’s Airport Task Force, were working together with the FAA on a revision of the FAA’s 150/5370-10 standard.
The entire construction guide specifications were revised during the review and revision process, including specifications for concrete pavement construction (P-501), aggregate base course (P- 209), cement-treated base course (P-304), and other specifications.
“We discussed the development of the FDR spec with the FAA so we could avoid going through modifications. They were receptive to the idea, which we advocated because it would give engineers the option using a specification instead of the cumbersome modification of standards,” Mitchell said.
He said almost daily conversations with key FAA officials were instrumental in identifying potential challenges and working through changes efficiently—notably Doug Johnson and Greg Cline: both Senior Civil Engineers and pavement subject matter experts (SME)-Office of Airports Safety and Standards-FAA Airport Engineering Division, Washington, DC..
On a parallel path, Mitchell said he was also having discussions with key personnel at Portland Cement Association (PCA) who recommended specification language, provided technical guidance, and joined in the discussion—namely Wayne Adaska, Director of Pavements & Geotechnical Markets-PCA and Dr. Paul Tennis, Director Product Standards & Technology-PCA, among others. He also credits long-time PCA Member Al Innes, VP Quality-Holcim and the MIT Sustainability Hub. Together, this group provided sound engineering judgment and technical information, which led to the FDR specification.
During the months-long process of marking up the FAA’s 5370-10 standard—now known as FAA Advisory Circular 150/5370-10H—Mitchell said Innis, PCA representatives, and the ACPA Airport Task Force provided excellent support and expertise. The Airport Task Force also participated in the reviews of the specs related to concrete pavement construction. Martin Holt, Corporate Quality Control Manager-Interstate Highway Construction, Inc.; Angela Folkestad, Executive Director-Colorado/Wyoming Chapter-ACPA; and Harold Honey, Project Manager-Michael Baker International participated in a comprehensive review and mark-up of the standard. Mitchell emphasized that long-term relationships and open and forthright discussions with Doug Johnson and Greg Cline also helped the revision process go smoothly. Gary is also quick to credit other organizations** that provided input on the standard.
As stated above, the net result of this team effort is a standard that now includes FDR specification language, which allows engineers to easily and quickly incorporate the FDR strategy into airport rehabilitation plans, while streamlining the overall pavement rehabilitation process. The ultimate beneficiaries are the airports, airport owners’ representatives, and of course the taxpaying public!
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* Full-depth reclamation (FDR) is one of several cement-based rehabilitation strategies, which involves recycling an existing asphalt pavement and its underlying layer(s) into a new base layer, according to the National Concrete Pavement Technology Center (CP Tech Center). FDR with cement increase the structural capacity of the new roadway by providing a stronger, more consistent base, the CP Tech Center says.
** Other organizations included: Airports Consultant Council, American Society of Civil Engineers (ASCE), Asphalt Institute, Geosynthetic Materials Association, and National Stone Sand Gravel Association.
Photo courtesy of Greg Dean, Executive Director-Carolinas Concrete Paving Association-SE Chapter ACPA. For the original article, please go to: http://www.acpa.org/fdr-airport-specs/?fbclid=IwAR3tqsGhMRV8MQFjuUSW28_WjSDSy_2VfkjasE-0_KdHq1MN_2sH5oGt8nk